This invention discloses an interlocking arrangement which can be used to secure plastic containers to each other. The invention is especially suitable for use with container systems for storing and dispensing film-processing chemicals.
Examples of the container systems in which the present invention can be used are found in U.S. Pat. No. 4,103,358, entitled "Fluid Mixing and Dispensing System" and U.S. Pat. application Ser. No. 929,174, filed July 25, 1978, entitled "Container for Film Processing Chemicals." Both the patent and the application cited above are incorporated by reference herein.
In container systems such as are described in the references cited, and particularly in the latter reference, there are provided a plurality of plastic containers having predetermined volumes, each container being distinct, and being designed to hold a particular chemical used in film processing. The container is intended to be inverted, and inserted into an appropriate receptacle in or over a film developing machine, so that the chemicals from the containers can flow directly into the appropriate storage tanks within the machine. Such a receptacle may consist of nothing more than a plurality of openings, through which chemicals are to be poured, or the receptacle could also be recessed, allowing the inverted container to be left in the machine while the chemicals are being poured out. The advantage of the container system of this type is that the proper chemicals, in the precise proportions, can be supplied to the machine, without the need to measure the amounts of the chemicals, and without the need to be concerned with which openings on the developing machine should receive which chemicals. Typically, the container system has indentations which correspond to protrusions in the receptacle portion of the developing machine, so that the container system can be inserted into the machine in only one way. This arrangement insures that the proper chemicals will be directed to the proper storage tanks.
In practice, it is often the case that the container system used for storing and dispensing film-processing chemicals comprises one large vessel, and at least two small containers which are designed to snap onto the larger vessel. In the prior art, the means for attaching the small plastic container to the large plastic vessel has been by using a mortise and tenon combination. However, this structure has proved unreliable, because during handling and transportation, the small containers are likely to separate from the large vessel.
The present invention solves the problem described above by providing a unique interlocking arrangement which prevents the small plastic container from disengaging from the larger plastic vessel. Although the invention is described with respect to one particular field of use, namely the storage and handling of film processing chemicals, it is understood that the interlocking arrangement could be used to hold plastic containers together in other contexts.